Antioxidants for mineral oil lubricants and compositions containing the same



'Patented Apr. 18, 1950 UNITED STATES PATENT OFFICE I-ANTIOXIDANTS FOR MINERAL on. LUBRI- CANTS AND COMPOSITIONS oonmmme THE SAME Herschel G. Smith, Wallingl'ord, and Troy'L. Cantrell, Lansdowne, Pa., and John G. Peters, Audubon, N. 1., assignors to Gulf Oil Corporation, Pittsburgh, Pa., a corporation of Pennsylvania No Drawing. Application September 3, 1947, Serial No. 772,014

38 Claims. (Cl. 252-515) are mixed and heated to a maximum temperature erating conditions are encountered, plain mineral lubricating oils often prove unsatisfactory in service because of the oxidative deterioration of the oil, with the attendant deposition on the engine surfaces of varnish, gum or sludge. Furthermore, many lubricating oil compositions which may be highly satisfactory for the lubrication of other mechanisms have been found wholly unsuitable for use as turbine oils.

The formation of varnishes, gums and sludges on engine surfaces is due at least in part to oxida-- tion effects on mineral lubricating oils. In turbine oils the problem of oxidation is further aggravated, because in normal use turbine oils rapidly become contaminated with water.

It is an object of this invention, therefore, to provide an addition agent for mineral oil lubricants which will inhibit the oxidativedeterioration of such lubricants.

It is further an object of this invention to provide improved mineral oil lubricant compositions which are remarkably stable against oxidation under service conditions.

These and other objects are accomplished by the present invention wherein an addition agent for mineral oil lubricants is prepared by condensing a monohydric phenol having at least one unsubstituted 'nuclear position, N-dimethylaniline and formaldehyde in the presence of an activated clay catalyst, and recovering the condensation product. The condensation product so obtained is' a light-colored product which, when added to mineral oil lubricants, confers a remarkable stability against deterioration by oxidation. Such condensation products and mineral oil lubricant compositions containing them are believed to be novel and are considered parts of our invention. Contrary to what may be expected from the nature of the reactants, we do not obtain highlycondensed, insoluble resinous products. On the contrary, when'the above reactants are condensed in accordance with our invention, there are obtained light-colored condensation products which are non-resinous and which are readily soluble in mineral oils.

In performing the condensation, the reactants of 350 F. We have found that if the temperature of 350 F. is exceeded to any substantial extent, the condensation product formed tends to be resinous and insoluble. The preferred temperature for the condensation ranges from 150 to 300 F. The proportions of the reactants may vary over a-relatively wide range. The monohydric phenol may be employed in an amount of from 1 to 4 mols; N-dimethylaniline may be employed in an amount of from 1 to 4 mols; and the amount of formaldehyde may range from 0.5 to 4 mols of formaldehyde per mol ofthe phenol. Or-

.2-nitro, 4-amino-pheno1,

dinarily, it is preferred to use from 5 to 10 per cent by weight of the activated clay catalyst, based on the total weight of the reactants. However, smaller amounts,- as low as 1 per centby weight, and larger amounts, as high as 20 per cent by weight, may also be employed; but larger amounts than about 10 per cent by weight are ordinarily not necessary.

The monohydric phenols which may be used in accordance with our invention include phenol itself and the substituted monohydric phenols having at least one unsubstituted nuclear position. Among the substituted phenols, we prefer to use the alkylated monohydric phenols, including monoand polyalkylated phenols, such as the ortho, meta and para cresols and mixtures thereof, such as cresylic acid, the various xylenols, phlorol, the isopropyl phenols, thymol, ortho and para tertiarybutyl phenol, 2,4-ditertiarybutyl phenol, 2,4,6-tritertiarybutyl phenol, ortho and para tertiaryamyl phenol, hexyl phenols, heptyl phenols, octyl phenols, particularly para tetramethylbutyl phenol, and the like. Other substituted phenols which we may employ include alkoxy phenols and mixed alphyl, alkoxy phenols, such as guaiacol, chavibetol, eugenol, isoeugenol and creosol. The latter compound, in particular, yields an excellent product. In addition, polynuclear monohydric phenols, such as alpha and beta naphthols, anthrols, phenanthrols, pyrenol and the like may also be employed. Other substituted phenols than alkyl, alkenyl, aryl and alkoxy phenols may be employed. These include the halo, nitro, amino and alkylamino phenols and the like. Examples of such phenols are ortho and para chlorophenol, para-amino-phenol, para dimethylamino phenol, etc. It will be seen, therefore, that the term monohydric phenol having at least one unsubstituted nuclear position includes both substituted and unsubstituted monohydric phenols which may be monocyclic or polynuclear.

In lieu of formaldehyde any formaldehydeyielding compound, such as paraformaldehyde, dionmethylene and trioxymethylene may be employed. In such case, the amount of formaldehyde-yielding compound used is based on the equivalent number of mols of formaldehyde yielded within the range of proportions of formaldehyde set forth hereinabove.- Accordingly, as used in the appended claims, the term formaldehyde" is intended to include formaldehyde-yielding compounds as well as formaldehyde itself.

Various activated clay catalysts may be employed in accordance with our invention. Such materials are well known in the art and comprise a natural clay, such as. bentonite, fuller's earth, floridin and smectite, which has been acid treated in order to activate the clay.

In preparing our new addition agent the reactants and catalyst are placed into a reaction vessel which is then closed and the mixture is heated with'agitation until all of the formaldehyde or formaldehyde-yielding compound has been consumed. At this time the water which is formed as a result of the condensation is removed, preferably under vacuum, andthe dehydrated condensation product is then filtered to remove the activated clay catalyst. In some in.- stances, it is desirable to prepare our new addition agent in a concentrate in a mineral lubricating oil which may then be diluted down with additional oil to the concentration desired in the final lubricating composition. In such instances, the mineral lubricating oil may be added in a suitable amount, say in a weight equal to the weight of reactants, to the'reaction mixture in the-reaction vessel, and the condensation product obtained will then be a concentrated.v solution was then heated to 160 F. at which-temperature 60.5 parts by weight of N-dimethylaniline and 40.5

parts by weight of a 87% by weight aqueous solution of formaldehyde were added. The reaction vessel was then closed and the temperature was raised to 210 F. at which point itwas maintained for a period of 6 hours while agitating. The water was then removed from the reaction mixture by applying a vacuum not exceeding 15 inches mercury pressure. The temperature was then raised to 300 F. and the mixture was agitated for 2 hours. The product was then cooled to 200-220 F. and filtered, preferably with the aid of a diatomaceous earth filter aid. The condensation product prepared in accordance with this example had the following properties:

Example II Into an iron reaction vessel were charged 108 pounds of cresylic acid, 242 pounds of N-dimethof the addition agent in the mineral lubricating oil.

The condensation products obtainedin accordance with our invention are liquids or crystalline solids. While we do not desire to be bound by any theory as to the reaction or reactions involved or the chemical composition of the products, we believe thatin view of the multiple points of the respective molecules at which the reactants may react, we obtain a mixture of chemical compounds. The exact nature of the manner in which the catalyst influences the reaction is unknown. However. regardless of any theory involved, the use of an activated clay catalyst is an essential feature of our invention, since if the catalyst is omitted, black, insoluble, resinous condensation products are obtained. a

The following examples illustrate the preparation of our new addition agents:

Example I Octyl phenol (para tetramethylbutyl phenol) was conveniently prepared by introducing 24.8 parts by weight of phenol and 31.4 parts by weight'of octene (di-isobutylene polymer) into a reaction vessel. The mixture was then agitated and 1.2 parts by weight of 94-98 per cent sulfuric acid were addedover a period of 30 minutes. After the addition of the sulfuric acid, the temperature was maintained at 220 F. fora periodv of 24 hours. The reaction mixture was then cooled to 180 F. and was washed three times with 10 parts by weight of water. The reaction temylaniline and 175 pounds of 37% aqueous formaldehyde along with 35 pounds of an activated clay catalyst. The mixture was refluxed and agitated at 210 F. for a period of 12 hours. The temperature was then raised to 280 F. and all water, both that added with the formaldehyde and formed in the reaction, was distilled off. The product was then filtered and had the following properties:

Gravity: AP 2.5 Color,NP 5.5 Neutralization No 1.96

From the nature of the composition of the cresylic acid it is noted that our addition agent prepared according to the above stated example would necessarily comprise a mixture of several closely related compounds such as (1) the condensation of ortho cresol with N-dimethylaniline and formaldehyde, (2) that of para cresol condensed with N-dimethylaniline and formaldehyde, and (3) that of meta cresol condensed with N-dimethylaniline and formaldehyde.

Example III I Another compound, in accordance with our invention, was conveniently prepared by placing 1 mol of thymol, 1 mol of N-dimethylanillne and 1 mol of formaldehyde (37% aqueous) into an iron reaction vessel. Into this vessel was added Gravity: AP 9.0 Color, NP 1.75 Y Neutralization No 1.24

Example IV A tertiaryamyl phenol was prepared by placing 94 pounds of phenol and 70 pounds of amylene into a pressure vessel. The vessel and its contents were then cooled to 70 F. Then, 5

pounds of 98% sulfuric acid were added to the mixture and the whole agitated for 2 hours.

4 After, the addition of sulfuric acid, the tempera ture was raised to F. and maintained at that temperature with agitation for a period of 10 activated clay catalyst were added. The mixture '15 hours. Then the reaction mixture was heated to 200 F., after which it was washed 3 times with parts by weight of water. The reaction temperature was never permitted to exceed 200 F. After washing, 242 pounds of N-dimethylaniline and 165 pounds of 37% aqueous formaldehyde were added to the mixture along with 40 pounds of an activated clay catalyst. The mix ture was stirred for 10 hours at 200 F. under reflux, was dried by heating to 280 F., and then filtered. The product had the following properties:

Gravity: API 5.3

Color, NPA 4.25

Neutralization No 1.22

Example V Into an iron reaction vessel were charged 144 pounds of alpha-naphthol, 242 pounds N-dimethylaniline, and 175 pounds of 37% aqueous formaldehyde along with 35 pounds of an activated clay catalyst. The approximate molar proportions of the ractants were 1 mol of alpha naphthol, 2 mols of N-dimethylaniline and '2 mols of formaldehyde. The mixture was refiuxed and agitated at 212 F. for a period of 12 hours. Thereafter, the temperature was raised to 280 F. and all water, both that added with the formaldehyde and formed with the reaction, was distilled off. The product was then filtered and had the following properties:

Gravity: "API 3.2 Color, NPA 3.5 Neutralization No 1.0

Example VI Gravity: API 3.4 Color, NPA 5.5 Neutralization No -1 2.4

Example VII Into an iron reaction vessel were charged 144 pounds of creosol, 242 pounds N-dimethylaniline, and 175 pounds of 37% aqueous formaldehyde along with 35 pounds of an activated clay catalyst. The approximate molar proportions of the reactants were 1 mol of creosol, 2 mols of N-dimethylaniline and 2 mols of formaldehyde. The mixture was refluxed and agitated at 212 F. for a period of 12 hours. Thereafter, the temperature was raised to 280 F. and all water, both that added with the formaldehyde and formed with the reaction, was distilled off. The roduct was then filtered and had the following properties.

Neutralization No Example VIII Into an iron reaction vessel were charged 256 pounds of tetramethylbutyl-beta-naphthol, 242

Gravity: API Color. NPA 2.5 Neutralization No 1.4

Example IX I Into an iron reaction vessel were charged 262 pounds of 2,4,6-tritertiarybutyl phenol, 363 pounds of N-dimethylaniline and 255 pounds of 37% aqueous formaldehyde along with 62 pounds of an activated clay catalyst. The mixture was refluxed and agitated at 210 F. for '12 hours,

and then the temperature was raised to 280 F. and all water, both that added with the formaldehyde and formed with the reaction, was distilled off. The product was then filtered and had the following properties:

Gravity: API u 12.1

Color, NPA 3.75

Neutralization No 0.1.2

Example X Into an iron reaction vessel were charged 206 pounds of 2,4-ditertiarybutyl phenol, '224 pounds of N-dimethylaniline, and pounds of 37% aqueous formaldehyde along with 42 pounds of an activated clay catalyst. The mixture was refluxed and agitated at 210 F. for 12 hours, and then the temperature was raised to 280 F. and all water, both that added with the formaldehyde and formed with the reaction, was distilled off. The product was then filtered and had the following properties:

Gravity: API 10.9 Color, NPA 5 Neutralization No 0.4

The condensation products obtained in accordance with the above disclosure from a monohydric phenol, N-dimethylaniline and formaldehyde in the presence of an activated clay catalyst are excellent addition agents for mineral oil lubricants. They are readily soluble in all types of mineral oils, that is, parafiinic, naphthenic or mixed base mineral oils and can be blended with mineral oils in high proportions to form concentrated solutions thereof, which may then be dfluted down to the proportions desired in the final mineral oil lubricant composition. As stated, our new addition agents are remarkably effective in inhibiting the oxidative deterioration of mineral oil lubricant compositions. For this purpose small amounts of our new addition agents are generally suflicient. For example, our addition agents may be added to mineral lubricating oils in minor amounts, say from 0.001 to 1 per cent by weight on the mineral oil, suflicient to inhibit the oxidative deterioration of the oil. Larger amounts of our new addition agents may be used if desired, but it is ordinarily unnecessary to do so.

The following examples illustrate the remarkable antioxidant effects of our new addition agents. In the following examples, the basev ofl and the same 011 blended with our new addition 7 agents are subjected to a standard oxidation test which measures the stability of the oils to oxidation. The oxidation test referred to is a standard test described in "AS'I'M Standards on Petroleum An improved steam turbine oil was prepared by treating a turbine base oil with 0.5 per cent by weight of an antioxidant prepared according to Example IV. A comparison of the properties oi. the base oil and improved turbine oil showed the iollowinzz Products and Lubricants, September, 1943, pages 17-20. Briefly, the test comprises subjecting the oil sample to oxygen at a temperature of 95 C. (203 F.) in the presence 01' water and an ironcopper catalyst, and determining the time required to build up a neutralization number of 2. 10 The flow of oxygen is maintained at 3 liters per hour. The remarkably eflective stability to oxidation of mineral oil lubricant compositions containing our new addition agents is illustrated by the results shown in the following examples: xv

An improved motor lubricating oil SAE 30 was Example XI 1 prepared by treating an SAE 30 base motor stock To a steam turbine oil having a viscosity of wi h Per cent by weight of the antioxidant 420 SUV at 100 F., there was added 0.5 er cent prepared according to Exampl IV- A co p riby weight of the addition agent prepared accordson of the properties of the base oil and the iming to Example I. The base oil and the oil proved oil showed: blended with the antioxidant were then subv.iected to a standard oxidation test with the following results: Base on gf Im roved Gravity, API 30.5 30.6 01 Con- Viscosity, SUV, 100 F. 240 239 Base Oil taining Color, NPA 2.0 2.0 v 0.57 Anti- Neutralization No 0.02 0.03

oxidant Oxidation Test,-ASTM-Proposed 203 F., s L.

Oxygen/Hm Time Oxidized, Hr 110 3, 500 Oxidation Test, ASTM-Proposed 203 F., Neutralization No 20 20 3 Oxygen/Hr; v Time Oxidized, m- 110 2,115 Neutralization No 2. 0 2.0

Example XVI Example XII An improved lubricating oil was prepared by treating a refined lubricating 011 base with 0.5 To a motor oil which had been highly refined per cent by weight f the additive prepared by an aluminum chlorid treatment there was cording to Example Comparison tests of the added 0.5 per cent by weight of the addition agent 40 base on and the improved on showed: prepared according to Example II. A com- I parison of the base oil and improved oil follows:

I Base on 33 Base Improved on on w s a: a: Gravity, s -1..-"; 28.2 28.0 co lg'if ti'imw 2.0 2.5 Viscosity, SUV, 130 F 249 24 Neutralization No 0.01 0.03 Color. PA 3- 5 5 Oxidation Test, ABTM-Proposed 203 F., 3 L. Neutralization N0 0. 02 0. 03 Oxygen/Hr; Oxidation Test, ASTM-Proposed 203 F., 3 L. Time Oxidized, Hr 210 2, 400 O en/Hr.: m Neutralization No 2.0 2.0 me Oxidized, Hr 195 2,600 I v Neutralization No 2. 0 2. 0

Example XVII I Example X] I I An improved lubricating oil was prepared by An improved lubricating oil was prepared by treating a refined lubricating oil base with 0.5 treating a refined lubricating 011 base with 0.5 per cent by weight of the additive prepared acv per cent by' weight of the additive prepared according to Example VI. Comparison tests oi the cording to Example III. A comparison 01 the base oil and the improved oil showed: base oil and the improved 011 showed the following results: 00

' Base on 3;?

Base Improved 011 on efl t t'id r 3'33 Gravity, API act 30.3 66 Color, NlAm: -II III 20 as Viscosity, SUV,-130 F 235 233 Neutralization No 0. 01 0.03 Color, NPA..; 2.0 2. 5 Oxidation Text, ASTM-Proposed 203 F., 3 L. Neutralization N0 0.01 0.03 Ox ge H11: Oxidation Test, ABTM-Proposed arr 11,3 L. 'l lme Oxidized, m 210 2, 500 m I 7 2m m Neutralization No 2-0 2.0 NeutralizationlIoLIIII:IIIIIII: 2.0 '20 I Example XVIII Example XIV An improved lubricating oil was prepared by treating a refined lubricating oil base with 0.5

cording to Example VII. Comparison tests of the base oil and the improved oil showed:

Base oil 'gfi 30. 5 30. 3 B5 233 NP a: a: Neutralization No..- 018d!!! ion ll'l iest, ASTM-Ptoposed 23 F.,3 L.

1 gen r.: I 'l lme Oxidized, Hi 210 .4,442 Neutralization No 2. 2. 0

Example XIX An improved lubricating oil was prepared by treating a refined lubricating oil base with 0.5 per cent by weight of the additive prepared according to Example VIII. Comparison tests of the base oil and the improved oil showed:

Base on 'gfl Gravity, API 30. 30.3 Viscosity, SUV, 130 F- an Zi-i Color, NPA Y 2 0 2. 5 Neutralization No 0. 0i 0. 03 Oxidation Test, ASTM-Proposed 203 F., 3 L.

Oxygen/Hr;

Time Oxidized, Hr 210 1, 550 Neutralization No 2. 0 2. 0

Example XX An improved steam turbine oil was prepared by treating a turbine oil base with 0.5 per cent by weight of an additive prepared according to Example IX. A comparison of the properties of the base oil and improved turbine oilshowed the following:

Base Oil gf Gravity, API 29. 2 29.0 Oxidation 'iest, AS'IM-Proposed 203 If 3 L.

Oxygen Hr;

Time Oxidized, Hr 210 3,245 Neutralization No 2.0 2.0

Example XXI An improved steam turbine oil was prepared by treating a turbine oil base with 0.5 per cent by weight of an additive prepared according to Example X. A comparison of the properties of the base oil and improved turbine oil showed the following: I

Base Oil g Gravity, API 29.2 29.0 Oxidation Test, ASIM-Proposed 203 F., 3 L.

Oxygen/Hm Time Oxidized, Hr 210 2,140 Neutralization N o 2.0 2. 0

i0 Thus. condensation products prepared from other functionally similar compounds have been found to be either pro-oxidant or to show no antioxidant preparation of com ounded lubricating oils, our

- The remarkable effects of our new addition agents cannot be readily accounted for and cannot be predicted from the nature of the reactants.

invention is not limited thereto but comprises all mineral oil lubricant compositions containing our new addition agents. such as creases and the like. If desired, other known addition agents may be incorporated into the lubricant compositions prepared in accordance with our inventoln. For example, pour point depressants, extreme-pressure agents and the like may be added.

- We claim:

1. The process of preparing an addition agent for mineral oil lubricants which comprises heating from 1 to 4 mols of a monohydric phenol having at least one unsubstituted nuclear position, i to 4 mol of N-dimethylaniline and 0.5 to 4 mols of formaldehyde per mol of the phenol in the presence of an activat d clav catalyst at a temperature not in excess of 350 F. to condense together the three reactants, and recovering the cond nsation product.

2. The process of preparing an addition agent for mineral oil lubricants which comprises heating from 1 to 4 mols of a monohydric phenol having at least one unsubstituted nuclear mention, 1 to 4 mols of N-dlmethylanilineand 0.5 to 4 mols of formaldehyde per mol of the henol in the presence of 5 to 10 per cent by weight on the total reactants of an activated clav catalvst at a temperature of from to 300 F. to condense together the three reactants, and recovering the condensation product.

3. The process of prepar ng an addition a ent for mineral oil lubricants which compri es adding from 1 to 4 mols of a monohydric phenol having at least one unsubstituted nuclear position. 1 to 4 mols of N-dimethvlaniline. 0.5 to 4 mols of formaldehyde per mol of the phenol, and an activated clay catalyst to a min ral lubricating oil, heatine the mixture to a tem erature not in excess of 350 F. to form a condensation product oi the three reactants, and recovering a solut on of the condensation product in the mineral lubrieating oil.

4. The process oi pre aring an addit on a ent for mineral o l lubricants which comnrises heating from 1 to 4 mols of an alkviated monohvdric phenol. 1 to 4 mols of N-diemthvlanil ne. and 0 5 to 4 mols of formaldehyde per mol of the phenol in the presence of an activated c av catalyst at a temperature not in excess of 350 F. to condense together the three reactants, and recovering the con ewation product.

5. The process of pre aring an addition agent for mineral oil lubricants which comprises heating from 1 to 4 mols of thymol, 1 to 4 mols of N-dimethylaniline and 0.5 to 4 mols oi formaldehyde per mol of thvmol in the presence of an activated clav catalyst at a temperature not in I l'l mols of N-dimethylaniline and 0.5 to 4 mols of formaldehyde per mol of octyl phenol in the preesnce of an activated clay catalyst at a temperature not in excess of 350 1'. to condense together the three reactants, and recovering the condensation product. a

7. The process of preparing an addition agent formineral oil lubricants which comprises heating about 1 mol of tetramethylbutyl phenol, about 2 mols of N-dimethylaniiine and about 2 mols of formaldehyde in the presence of about per cent by weight on the reactants of an activated clay catalyst at a temperature of from 150' to 300 F. to condense together the three reactants, and recovering the condensation product.

8. The process of preparing for mineral oil lubricants which comprises heating 1 mol of thymol. 1 mol of N-dimethylaniline and 1 mol of formaldeh de in the presence of aboutlO per c nt by wei ht on the total reactants the total reactants of an activated clay catalyst an addition agent Y at a temperature of from 150' to 300' F. to condense together the three reactants, and recovering the condensation product.

15. A non-resinous condensation product of from 1 to 4 mols of a monhydric phenol having at least one unsubstituted nuclear position, 1 to 4 mols of N-dimethylaniline and 0.5 to 4 mols of formaldehyde per mol of the phenol, said prodnot being obtained by the process of claim 1.

16. A non-resinous condensation product of from 1 to 4 mols of an alkylated monohydric phenol, 1 to 4 mols of N-dimethylaniline and 0.5 to 4 mols of formaldehyde per mol of the phenol, saaiilmpzoduct being obtained by the process of c 17. A non-resinous condensation product of,

, from 1 to 4 mols of an octyl phenol, 1 to 4 mols of an a tivated clay catalyst at a temperature of from 150 to 300 F. to condense together the three reactants, and recovering the condensation product.

9. The process of preparing an addition agent for mineral oil lubricants which com rises heating from 1 to 4 mols of a nanhthol. 1 to 4 molsof N-dimethylaniline and 0.5 to 4 mols of formaldehyde per mol of the naphthol in the presence of an activated clay catalyst at a temperature not in excess of 350 F. to condense together the three reactants, and recovering the condensation product.

10. The process of pre aring an addition agent for mineral oil lubricants which com rises heating from 1 to 4 mols of alpha naphthol, 1 to 4 mols of N-dimethylaniline and 0.5 to 4 mols of formaldehyde per mol of the nanhthol in the presence of an activated clav catalyst at a tem- 7 perature not in excess of 350 F. to condense together the three reactants, and recovering the condensation product.

11. The process oi preparing an addition agent for mineral oil lubricants which com rises heating about 1 mol of alpha naphthol, about 2 mols of N-dimethylaniline and. about 2 mols of formaldehyde in the presence of about 10 per cent by hydric phenol, 1 to 4 mols of N-dimethylaniline and 0.5 to 4 mols of formaldehyde per mol of the of N-dimethylaniline and 0.5 to 4 mols of formaldehyde per mol of octyl phenol, said product being obtained by the process of claim 6.

18. A non-resinous condensation product of about 1 mol of tetramethylbutyl phenol, about 2 mols of N-dimethylaniline and about 2 mols of formaldehyde, said product being obtained by the process of claim 7.

19. A non-resinous condensation product of from 1 to 4 mols of thymol, 1 to 4 mols of N-dimethylaniline and 0.5 to 4 mols of formaldehyde per mol of thymol. said product being obtained by the process of claim 5.

20. A non-resinous condensation product of 1 mol of thymol, 1 mol of N-dimethylaniline and 1 mol of formaldehyde, said product being obtained by the process of claim 8.

21. A non-resinous condensation product of from 1 to. 4 mols of a naphthol, 1 to 4 mols of N-dimethylaniline and 0.5 to 4 mols of formaldehyde per mol of the naphthol, said product being obtained by. the process of claim 9.

. 22. A non-resinous condensation product of from 1 to 4 mols'of alpha naphthol, 1 to 4 mols of N-dimethylaniline and 0.5 to 4 mols of formaldehyde per mol of the alpha naphthol, said product being obtained by the process of claim 10.

- '23. A non-resinous condensation product of about 1 mol of alpha naphthol, about 2 mols of N-dimethylaniline and about 2 mols of formaldehyde, said product being obtained by the process of claim 11. a

24. A non-resinous condensation product of from 1 to 4 mols of analphyl, alkoxy monohydric phenol, 1 to 4 mols of N-dimethylaniline and 0.5

phenolin the presence ofan activated clay catalyst at a temperature not in excess of 350 F. to

condense together the three reactants, and recovering the condensation product.

'13. The process of pr paring an addition agen for mineral oil lubricants which comprises heating from 1 to 4 mols of creosol, 1 to 4 mols of N-dimethylaniline and 0.5 to 4 mols of formaldehyde per mol Tof the creosol in the presence of an activated clay catalyst at a temperature not in for mineral oil lubricants which comprises heating about 1 mol of creosol, about 2 mols of N-dimethylaniline and about 2 mols of formaldehyde in the resence of about 10 per cent by weight on to 4 mols of formaldehyde per mol of the phenol,

I said product being; obtained by the process of claim 12.

25. A non-resinous condensation product of from 1 to 4 mols of creosol, 1 to 4 mols of N-dimethylaniline and 0.5 to 4 mols of formaldehyde per mol of creosol. said product being obtained by the process of claim 13.

26'. A' non-resinous condensation product of about 1 mol of creosol, about 2 mols of N-dimethylaniline and about 2 mols of formaldehyde, said product being obtained by the process of claim 14.

' 27. A lubricant composition comprising a major amount of a mineral lubricating oil, and a minor amount, .sufflcient to inhibit the oxidative deterioration of said oil, of a non-resinous condensation product of from 1 to 4 mols of a monohydric phenol having at least one unsubstituted nuclear position, 1 to 4 mols of N-dimethylaniline and 0.5 to 4 mols of formaldehyde per mol 13 of the phenol, said product being obtained by the process of claim 1.

28. A lubricant composition comprising a major amount of a mineral lubricating oil, and a minor amount, from 0.001 to 1.0 per cent by weight of said oil, of a non-resinous condensation product of from 1 to 4 mols of a monohydric,

phenol having at least one unsubstituted nuclear position, 1 to 4 mols of N-dimethylaniline and 0.5 to 4 mols of formaldehyde pei mol of the phenol, said product being obtained by the process of claim 1.

29. A lubricant composition comprising a major amount of a mineral lubricating oil, and a minor amount, sufficient to inhibit the o'xidative deterioration of said oil, of a non-resinous condensation product of from 1 to 4 mols of an alkyl-' ated phenol, 1 to 4 mols of N-dimethylaniline and 0.5 to 4 mols of formaldehyde per mol of the phenol, said product being obtained by the process of claim 4.

30. A lubricant composition comprising a major amount of a mineral lubricating oil, and a minor amount, from 0.001 to 1.0 per cent by weight of said oil, of a non-resinous condensation product of 1 mol of thymol, 1 mol of N-dimethylaniline and 1 mol of formaldehyde, said product being obtained by the process of claim a.

31. A lubricant composition comprising a major amount of a mineral lubricating oil, and aweight of said oil, of, a non-resinous condensation product of about 1 mol of tetramethylbutyl phenol, about 2 mols of N-dimethylaniline and about 2 mols of formaldehyde, said product being obtained by the process of claim 7.

33. A lubricant I composition comprising a major amount of a mineral lubricating oil, and a minor amount, sufficient to inhibit the oxidative deterioration of said oil, of a non-resinous condensation product of from 1 to 4 mols of a naphthol, from 1 to 4 mols of N-dimethylanlline and 0.5 to 4 mols of formaldehyde per mol of the naphthol, said product being obtained by the process of claim 9.

34. A lubricant composition comprising a major amount of a mineral lubricating oil, and a minor amount sumcient to inhibit the oxidative deterioration of said oil. of a non-resinous condensation product of from 1 to 4 mols of amhanaohtboLlto4molsofli-dhnethylenmne 14 and 0.5 to 4 mols of formaldehyde per mol or the alpha naphthol, said product being obtained by the process of claim 10.

35. A lubricant composition comprising a I major amount of a mineral lubricating oil, and

a minor amount, from 0.001 to 1.0 per cent by weight of said oil, of a non-resinous condensation product of about 1 mol of alpha naphthol, about 2 mols of N-dimethylaniline and about 2 mols of formaldehyde, said product being obtained by the process of claim 11.

36. A lubricant composition comprising a major amount of a mineral lubricating oil and a minor amount, sufficient to inhibit the oxidative deterioration of said oil, of a non-resinous condensation product of from 1 to 4 mols of an alphyl, alkoxy monohydric phenol, 1 to 4 mols of N-dimethylaniline and 0.5 to 4 mols of formaldehyde per mol of the phenol, said product being obtained by the process of claim 12. V 1

37. A lubricant composition comprising a major amount of a mineral lubricating oil and a minor amount, sufficient to inhibit the oxidative deterioration of said oil, of a non-resinous condensation product of from 1 to 4 mols of creosol, 1 to 4 mols of N-dimethylaniline and 0.5 to 4 mols of formaldehyde per mol of creosol, said product being obtained by the process of claim 13. 38. A lubricant composition comprising a major amount of a mineral lubricating-oil, and a minor amount, from 0.001 to 1.0 per cent by weight of said oil, of a non-resinous condensation product of about 1 mol of creosol, about 2 mols of N-dimethylaniline and about 2 mols of formaldehyde, said product being obtained by the process of claim 14.

HERSCHEL G. SMITH.

TROY L. CAN'I'REH... JOHN G. PETERS.

I REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,594,983 Sommerville c Aug. 3, 1926 2,097,162 Musselman Oct. 26, 1937 2,113,599 Musselman Apr. 12, 1933- 2.281,401 Wilson Apr. 28, 1942 2,336,006 Fuller Dec. '1. 1943 2,340,036 Zimmer Jan. 25, 1944 2,363,134 McCleary Nov. 21, 1944 2,431,011 Zimmer Nov. 13, 194'! OTHER REFERENCES Btreeker, Am. 334, 334-42 (1904). Smith et at. "J. Chem. Soc." (London). 1334. 1130-40. 

1. THE PROCESS OF PREPARING AN ADDITION AGENT FOR MINERAL OIL LUBRICANTS WHICH COMPRISES HEATING FROM 1 TO 4 MOLS OF A MONOHYDRIC PHENOL HAVING AT LEAST ONE UNSUBSTITUTED NUCLEAR POSITION, 1 TO 4 MOLS OF N-DIMETHYLANILINE AND 0.5 TO 4 MOLS OF FORMALDEHYDE PER MOL OF THE PHENOL IN THE PRESENCE OF AN ACTIVATED CLAY CATALYST AT A TEMPERATURE NOT IN EXCESS OF 350*F. TO CONDENSE TOGETHER THE THREE REACTANTS, AND RECOVERING THE CONDENSATION PRODUCT. 